Mechanical mixing bowl



2 Sheets-Sheet 1 v R. E. IRISH -MECHANICAL MIXING BOWL w/mfi Jiln-INNER:

Nov. 30, 1948.

Filed Sept. 18, 1946 INVENTORv flusseZZE. Z *is h WM 22. 41%

M aflorwa Nov. 3%, 1948. R. E. IRISH I MECHANICAL MIXING BOWL 2Sheets-Sheet 2 Filed Sept. 18, 1946 INV ENTOR Russell .E .l'rl'sh 5 44%,3.61%

Patented Nov. 30, 1948 siren STATES PATENT orrics MECHANICAL MIXING BOWLRussell E. Irish, Pittsburgh, Pa.

Application September 18, 1946, Serial No. 697,752

12 Claims. 1

This invention relates to a mechanical mixing bowl. and particularly toa mechanical mixing bowl which has its greatest utility in the mixingand spatulation of dental investment material, in the mixin andspatulation of pharmaceutical preparations such as emulsions, pillmasses, and in the mixing and smoothing of'fine plasters and enamels.

In uses such as those specifically named and in other uses of likesort,'it is highly desirable that the mechanical action be rapid andthat its efiect on the material subjected to it be such as completely toeliminate air bubbles and to give a thoroughly mixed, smooth preparationof the desired consistency. It is, however, also highly desirable thatthe bowl itself be flexible in order to facilitate accurate pouring fromit; that it be instantaneouslyremovablefrom the means which providemechanical propulsion, to expedite pouring; that the bowl and themechanical elements immediately associated w th it be susceptible ofthorough and rapid cleansing, to prevent the material which has beenprepared in the bowl from hardening therein or otherwise tending tocause deterioration of the bowl itself. or of its associ ated elements;and that the mechanical elements be so connected with the flexible bowlthat leakage from the bowl is prevented.

In accordance with my invention I provide a mixing bowl possessing aconjunction of such desirable properties. Additionally, I provide anorganization comprising power-actuated mechanical elements in which theagitator element is readily adjustable on and removable from itscarrying element, and in which selected sizes and shapes of agitator arereadily interchangeable to suit the specific material which is to bemixed in the bowl, the desiredconsistency of the mixed material and theamount ofspatulation which is desired.

In the accompanying drawings, illustrative of an apparatus embodiment ofmy invention:

Fig I is a view showing in elevation the casing for an electrical motorandthe mechanical elements associated with the flexible bowl of theassembly, the flexible bowl itself being shown in vertical section toexpose its associated mechanical elements.

Fig. II is a plan view of the assembly shown in Fig. I.

Fig. III is a fragmentary vertical section on an enlarged scale, takenthrough'the lower region of the flexible bowl itself and through the connections and mechanical operating means associated directly therewith,showing the shaft of the electrical motor from which propelling power isderived engaged with the mechanical operating elements within the bowl.Fig. IV is a bott-omplan view of'the inner of two retaining plates whichengage the base of the flexible bowl between them. I

Fig. V is a vertical sectional detail View on a smaller scale takenthrough the agitator-carrying element of the assembly. Fig. VI is avertical sectional view on the scaleof Fig. V, taken through the outerof the two re--'- taining plates and an agitator-mounting postv carriedthereby. r '1. Figs. VII, VIII and IX of the drawings, all of which areassumed to be on the scale of Figs. III and IV, show three agitators ofdifierent sizes for application selectively to the same agitator--carrying element. I

Referring to the drawings, reference'numeral l designates the casing ofan electrical motor, to which leads electrical conductor 2 and which hasswitch operating means 3. As will appear, this motor has a verticalshaft cooperatively arranged with respect to the mechanical elements ofthe mixing bowl assembly to impart power actuation thereto.

The mixing bowl 4 itself, is composed of suitableflexible material,typically rubber, and the other elements of the assembly are formedand'arranged with respect to the bowl and the motor shaft and casing togive full benefit of the known properties of a flexible mixing bowlwhilecombining those benefits with the advantages of power-actuatedagitation. As shown, in base 5 of flexible bowl 4 is relatively flat andis engaged between an outer plate 6 and an inner plate "I. Each of theseplates is provided with a set of three screw holes, the screw holes ofwhich sets are designated respectively 8 and 9 and are ar; ranged toregister with each ,otherand withholes' through the base of the bowl.When screws iii are inserted from within the bowl and the screws are rundown, plates 6 and l clamp base 5} of the bowl between them. Desirablythe firmness of this engagement is increased by roughening the; underface of inner plate 1, as by the circular" ridges ll shown most clearlyin Figs. III and IV [3, which is open at both ends and into which:vertical motor shaft It substantially extends.

This tubular post i3 projects through a central opening IS in the innerplate I andthrough a matching central Opening in the base of the bowland reaches upwardly in the interior of the bowl a substantial distance,which as shown brings its upper end approximately even with the upperedge of the bowl. The bowl 4 being composed of suitable flexiblematerial, such as rubber, its engagement between plates 5 and I andaround tubular post 13 makes a liquid-tight seal at the base, of thebowl, and the upward extension of integrally-mounted tubular post l3continues that liquid-tight feature upwardly and interiorly of the bowl.

The agitator assembly is carried by tubular post [3 in cooperativeengagement with the motor shaft. This assembly comprises anagitatorcarrying element, a motor shaft-engaging element and a bladedagitator. The agitator-carrying element is shown as a sleeve l6, whichextends downwardly along tubular post is into the lower region withinthe bowl. At its upper end sleeve 16 is closed, as by a cap or plug II,and depending interiorly from the upper end of the cap or plug I"! thereis an actuating rod l8. Between rod [8 and the interior of sleeve Hithere is an annular space l9, best seen in Fig. V, which is ofsuflicient width to receive tubular post [3.

In assembly, as shown in Fig. III, sleeve 16 is placed on post [3 withthe post inserted in annular space 18 and is allowed to move downwardlythereover, until cap or plug ll of the sleeve rests on the upper end, ofthe post. As so positioned rod l8 extends downwardly within post [3 tomake engagement with motor shaft l4. Such engagement is removably madeby means of a. kerf 20 in the upper end of the motor shaft and a spline2| at the lower end of actuating rod l8.

With flexible bowl 4 and its operating element removably placed on motorcasing I and with operating rod l8 engaged with motor shaft 14,actuation of the motor shaft, rotates agitatorcarrying sleeve 16 ontubular post l3. The agitator proper, which may be assumed to be of thesize shown in Figs III and VII, comprises a collar 22 adapted to embracesleeve [6, a setscrew 23 passed through the collar to bear against thesleeve and a plurality of angularly set blades 24. Engagement of theagitator with its carrying sleeve'by means of the collar and set-screwpermits adjustment of the agitator at different vertical levelstherealong, and renders it readily mountable on and removable from thesleeve. For different materials acted on in the bowl, it is therefore asimple matter to replace an agitator of one size with a larger orsmaller agitator of a size particularly suitedto the work which is to bedone. Thus in Figs. VIII and IX I show agitators having respectivelyblades 24a and 24b which are progressively smaller than the blades 24 ofthe agitator shown in Fig. VII. Collars 22a and 22b of the agitatorsshown respectively in Figs. VIII and IX are, however, of the same borediameter as the collar 22 of the agitator shown in Fig. VII and areequipped with similar set-screws 23a and 232). Since the desired effectusually is a smoothing action, exerted downwardly of the bowl withoutsplashing, the inclination of the agitator blades with respect to thedirection of rotation of the motor is such as to press the materialbeing agitated downwardly in the bowl and fixed means are provided tointensify the action. Such fixed means, which cooperate to increase theeffect of the agitator blades, is shown as up-startin vanes 25 extendedradially of and beyond inte- 4 rior plate I and desirably made integraltherewith.

The removability of the mixing bowl assembly from its operative mountedposition of the motor casing, conjointly with the flexibility of thebowl itself contributes greatly to the utility of the organization. Themounting of the mixing bowl assembly is such as to hold it against thetorque of the motor shaft withoutretarding its removal from the 'motorcasing. For this purpose the shanks of screws ill which project beyondthe outer plate 6 are smoothed to form positioning pins 25 which enterapproximately placed holes in the upper wall 21 of motor casing I. Thisprovides engagement against turning movement under the torque of themotor shaft, without preventing the bowl assembly being lifted from themotor casing.

To describe in detail a complete service use of the mixing bowlassembly, the bowl is placed in the motor casing in such position thatpins 26 enter their receiving holes in upper wall 21 of the motor casingand motor shaft l4 extends upwardly into tubular post l3. The agitatorassembly is mounted on post I3 either before or after positioning of thebowl, and it is a simple matter to bring spline 2i on rod I8 intoregistering engagement with kerf 20 of the motor shaft. The mixingaction is then performed with spatulating effect on the material in thebowl; it being possible to introduce all ingredients at once, or to addfinely divided solid material, such as the material for dentalinvestment gradually and without splashing to liquid in the bowl.

When the mixing has been completed, the bowl assembly is lifted from themotor casing, and it is to be noted that it can be removed instantly andwithout operating any fastening means, merely by a straight liftingaction. The agitator assembly is lifted from tubular post 13, againwithout loosening any fastening means, and can be set aside forcleansing.

The bowl is then in condition to pour its contents, and because of itsflexibility the bowl can be distorted to any desired extent to give apouring lip of a shape suitable for finely directing or distributing thecontents of the bowl. In this pouring, the substantial upward extent oftubular post 13 prevents the escape of slurry from the bowl by way ofthe post, and the firmly clamped engagement of the bowls base betweenthe retaining plates prevents the opening of any avenue of leakage asthe body of the bowl is distorted.

The facility and speed with which the bowl can be lifted should beemphasized, because it permits the pouring to be done before thecontents of the bowl can begin undesirably to thicken and at an instantproperly timed'with respect to other incidents of the particularoperation which is in progress. Also the flexibility of the bowlprovides for finely directed pouring with one hand, leaving the otherhand free for other operations on the work. It is understood of coursethat the advantages of a flexible bowl have in themselves been obtainedby flexible bowls as previously known. It is to be borne in mind,however, that the mixing bowl assembly of my invention combines thoseadvantageswith the advantages of power-actuated agitation, and bymechanical means which transmit that actuation in optimum manner, whichare proof against leakage, which are non-obstructive and which arethemselves structurally simple.

After'pouring the contents of the bowl, the

bowl and its associated mechanical elements readily are cleansed, as byholding them'under a jet of water. In thecleansing, the bowl can beturned inside out, without obstruction by the retaining plates and theelements integrated with them, the more effectively to present theinterior surface of the bowl itself and the surfaces of the tubular postand the fixed vanes to a cleansing jet.

The bowl proper of my mechanical mixing bowl assembly has been describedas flexible and it has been indicated that it is composed of a suitableflexible material, typically rubber. It is to be understood of coursethat it may becomposed of any of the so-called synthetic rubbers, orother plastics which are rendered suitable by approaching rubber inendurance, chemical resistance and elastomeric properties. The retainingplates and the otherassociated mechanical elements typically arecomposed of any metal which is suitable in strength and rigidity, butmost desirably are composed of a metal or alloy which additionally isresistant to abrasion, and chemical action, and which is of attractiveappearancc.

The primary object of my-invention, as explained above, is to equip aflexible mixing bowl in satisfactory manner with means for producingpower-actuation of an agitator within the bowl. Certain featuresinvolved in the embodimerit of my invention provide, however,meritorious improvement in the assembly even though the bowl itself beof rigid structure.

Having disclosed in detail one physical embodiment of my invention it isto be understood that I do not intend to limit myself to structuraldetails as herein illustrated or described, but that my invention is tobe assumed to embrace such changes and modifications as come within thescope of the claims appended hereto.

I claim as my invention:

1. In a mechanical mixing bowl assembly comprising an encased electricalmotor having a vertical shaft, the combination of a flexible-bowl, twoopposed plates arranged respectively inside and outside the said bowland engaging the base of the bowl between them over a major proportionof the area of said base, a tubular agitator-mounting and motorshaft-receiving post extended upwardly from the base of said bowl, anagitator-carrying element rotatable on said tubular post and arranged toengage the motor shaft therewithin, and means on the outer of the twosaid plates arranged to position the said flexible bowl on the motorcasing against the torque of the motor shaft.

2. In a mechanical mixing bowl assembly the combination of a flexiblebowl, opposed inner and outer plates directly connected with each otherthrough the base of the bowl and engaging the base of the bowl betweenthem to form an integrated element of the bowl without preventing thesaid bowl from being turned inside-out for cleansing, andagitator-carrying and motor shaft-engaging means carried by one of saidplates.

3. In a mechanical mixing bowl assembly the combination of a flexiblebowl, and two opposed plates one of them having a tubularagitatormounting post integral therewith directly connected with eachother through the base of the bowl and engaging the base of saidflexible bowl between them over the major proportion of the area of said.base to form an integrated element of the bowl-without preventing the.saidbowl being turned inside-out for cleansing.

4. -In a 'mechanicalmixing bowl assembly the combination of a bowl,opposed inner and outer plates directly connected with each other andengaging thebase, of said bowl between them to form an integratedelement of the bowl, a hollow motor shaft-receiving andagitator-mounting member extended upwardly from the base of the bowl, anagitatorecarrying and motor shaft-engaging element rotatable on andextended into said hollow member, an encased motor having a verticalshaft engageable with the agitator of said bowl, a plurality of vanesextended upwardly and horizontally from the upper face of said innerplate, and means on the outer of said plates arranged positively toposition the bowl on the motor casing against the thrust of the motorshaft without obstructing lifting the bowl from the casing.

5. In a mechanical mixing bowl assembly the combination of a bowl,retaining plates positioned respectively inside and outside the base ofsaid bowl'directly connected with each other and'engaging the said "basebetween them over the major proportion of the area of said base to forman integrated element of the bowl, a tubular motor shaft-receiving andagitator mounting member extended upwardly within the bowl from one ofsaid plates, an agitator-carrying element rotatable on said upwardlyextended member, a plura'lity' of vanes extended upwardly andhorizontally from the upper face of said inner plate, an agitator onsaid agitator-receiving element having; blades arranged to forcematerial downwardly in said bowl and againstsaid vanes and an electricalmotor having a shaft engaged with said agitator-carrying element.

6. In a mechanical mixing bowl assembly the combination of a flexiblebowl, retaining plates positioned respectively inside and outside, thebase of said bowl directly connected with each other and engaging thesaid base between them over themajor proportion of the area of said baseto form an'integrated element of the bowl, a tubular motorshaft-receiving and agitator-mounting member extended upwardly withinthe bowl from one of said plates, an electrical motor having a shaftextended into the said tubular member, an agitator-carrying sleeverotatable on said tubular member and engaged with the motor shafttherein, and a bladed agitator having blades arranged to force materialdownwardly in the bowl mounted on said sleeve and vertically adjustablethereon.

7. In a mechanical mixing bowl assembly the combination of a flexiblebowl, retaining plates positioned respectively inside and outside thebase of said bowl directly connected with each other through the base ofthe bowl and engaging the said base between them from an integratedelement of the bowl, a tubular motor shaft-receiving andagitator-mounting member extended upwardly within the bowl from one ofsaid retaining plates, an encased motor having a shaft extended intosaid tubular member, an agitatorcarrying member rotatable on saidtubular member and engaging the motor shaft therein, and means on saidouter retaining plate arranged to engage the bowl with the casing of themotor against the torque of the motor shaft, without obstructing removalof the bowl from the motor casing.

8. In a mechanical mixing bowl assembly the combination of a flexiblebowl, retaining plates positioned respectively inside and outside thebase of said bowl directly connected with each other and engaging thebase of the bowl between them to form anintegrated element of the bowl,a tubular motor shaft-receiving and agitator-mounting member extendedupwardy within the bowl from one of said retaining plates, an encasedmotor having a shaft extended into said tubular memher, anagitator-carrying sleeve rotatable on said tubular member and engagingthe motor shaft therein, a plurality of vanes extended upwardly andhorizontally from the upper face of said inner retaining plate, a bladedagitator having blades arranged to force material downwardly in the bowland against said vanes mounted on said sleeve and vertically adjustablethereon, and means on said outer retaining plate arranged to engage thebowl with the casing of the motor against the torque of the motor shaftwithout obstructing removal of the bowl from the motor casing.

9. In a mechanical mixing bowl assembly the combination of a flexiblebowl, motor shaft-receiving and agitator-mounting opposed inner andouter retaining plates engaging the base of said flexible bowl inclamping engagement between them to introduce the shaft of an electricalmotor in leak-proof manner thereinto and to maintain the base of thebowl leak-proof against distortion of the body of the bowl in pouring.

10. In a mechanical mixing bowl assembly the combination of a flexiblebowl, opposed retaining plates placed respectively inside and outsidethe base of said bowl, and tightening screws extended through both saidplates and through the base of the bowl between them to clamp the saidbase between the said retaining plates, the shanks of the said screwsbeing extended beyond the said outer plate to provide positioning pinsfor engaging the bowl to the casing of an electrical motor withoutobstructing removal of the bowl therefrom.

11. In a mechanical mixing bowl assembly the combination of a flexiblebowl, opposed retaining plates placed respectively inside and outsidethe base of said bowl, tightening means extended through both saidplates and through the base of the bowl between them to clamp the saidbase between the said retaining plates and to integrate the said platesas an element of the bowl, and a tubular agitator-mounting post extendedfrom said outer plate said inner plate and the base of the bowl betweenthem upwardly into the interior of the bowl to introduce a motor shaftin leak-proof manner into the bowl.

12. In a mechanical mixing bowl assembly the combination of a flexiblebowl, opposed reta;ning plates placed respectively inside and outsidethe base of said bowl, tightening screws extended through both saidplates and through the base of the bowl between them to clamp the saidbase between the said retaining plates over the major proportion of thearea of said base and to integrate the said plates as an element of thebowl, the shanks of the said screws being extended beyond the said outerplate to provide positioning pins for engaging the bowl to the casing ofan electrical motor without obstructing removal of the bowl therefrom,and a tubular agitatormounting post extended from said outer plate saidinner plate and the base of the bowl between them upwardly into theinterior of the bowl to introduce a motor shaft in a leak-proof mannerinto the bowl, and a bladed agitator carried by means mounted on saidpost and having blades arranged to force material downwardly in thebowl.

RUSSELL E. IRISH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,141,358 Portmann June 1, 19151,839,082 Burgard Dec. 29, 1931 1,930,948 Brewer Oct. 17, 1933 2,226,372Cravaritis Dec. 24, 1940 2,284,155 Landgraf May 26, 1942 2,304,476Poplawski Dec.8, 1942

